Community | August 18, 2009 | 8 comments

As Arctic Ocean warms, megatonnes of methane bubble up

source: http://www.newscientist.com/article/dn17625-as-arctic-ocean-warms-megatonnes-of-methane-bubb...

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JanforGore
It's been predicted for years, and now it's happening. Deep in the Arctic Ocean, water warmed by climate change is forcing the release of methane from beneath the sea floor.

Over 250 plumes of gas have been discovered bubbling up from the sea floor to the west of the Svalbard archipelago, which lies north of Norway. The bubbles are mostly methane, which is a greenhouse gas much more powerful than carbon dioxide.

The methane is probably coming from reserves of methane hydrate beneath the sea bed. These hydrates, also known as clathrates, are water ice with methane molecules embedded in them.

The methane plumes were discovered by an expedition aboard the research ship James Clark Ross, led by Graham Westbrook of the University of Birmingham and Tim Minshull of the National Oceanography Centre, Southampton, both in the UK.

Warm gas

The region where the team found the plumes is being warmed by the West Spitsbergen current, which has warmed by 1 °C over the past 30 years.

"Hydrates are stable only within a particular range of temperatures," says Minshull. "So if the ocean warms, some of the hydrates will break down and release their methane."

None of the plumes the team saw reached the surface, so the methane was not escaping into the atmosphere and thus contributing to climate change – not in that area, at least. "Bigger bubbles of methane make it all the way to the top, but smaller ones dissolve," says Minshull.

Just because it fails to reach the surface doesn't mean the methane is harmless, though, as some of it gets converted to carbon dioxide. The CO2 then dissolves in seawater and makes the oceans more acidic.

And it is possible that other, more vigorous plumes are releasing methane into the atmosphere. The team studied only one group of plumes, which were in a small area and were erratic.

"Almost none of the Arctic has been surveyed in a way that might detect a gas release like this," Minshull says.


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  1. groups:
    Community,   Green,   Earth and Science,   Science,   1 more
  2. tags:
    Climate Change,  CO2,  Glacier Melt,  Methane,  3 more
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